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| author | Omar Sandoval <osandov@fb.com> | 2020-03-02 14:02:49 -0800 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2020-03-03 15:26:08 +0100 |
| commit | e7a04894c766daa4248cb736efee93550f2d5872 (patch) | |
| tree | 500ed1c5e3a81c03d1c70c7c3f3e44e476a154e5 /fs | |
| parent | a5ae50dea9111db63d30d700766dd5509602f7ad (diff) | |
| download | linux-e7a04894c766daa4248cb736efee93550f2d5872.tar.bz2 | |
btrfs: fix RAID direct I/O reads with alternate csums
btrfs_lookup_and_bind_dio_csum() does pointer arithmetic which assumes
32-bit checksums. If using a larger checksum, this leads to spurious
failures when a direct I/O read crosses a stripe. This is easy
to reproduce:
# mkfs.btrfs -f --checksum blake2 -d raid0 /dev/vdc /dev/vdd
...
# mount /dev/vdc /mnt
# cd /mnt
# dd if=/dev/urandom of=foo bs=1M count=1 status=none
# dd if=foo of=/dev/null bs=1M iflag=direct status=none
dd: error reading 'foo': Input/output error
# dmesg | tail -1
[ 135.821568] BTRFS warning (device vdc): csum failed root 5 ino 257 off 421888 ...
Fix it by using the actual checksum size.
Fixes: 1e25a2e3ca0d ("btrfs: don't assume ordered sums to be 4 bytes")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/inode.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 1ccb3f8d528d..27076ebadb36 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7783,6 +7783,7 @@ static inline blk_status_t btrfs_lookup_and_bind_dio_csum(struct inode *inode, { struct btrfs_io_bio *io_bio = btrfs_io_bio(bio); struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio); + u16 csum_size; blk_status_t ret; /* @@ -7802,7 +7803,8 @@ static inline blk_status_t btrfs_lookup_and_bind_dio_csum(struct inode *inode, file_offset -= dip->logical_offset; file_offset >>= inode->i_sb->s_blocksize_bits; - io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset); + csum_size = btrfs_super_csum_size(btrfs_sb(inode->i_sb)->super_copy); + io_bio->csum = orig_io_bio->csum + csum_size * file_offset; return 0; } |